Allylmercaptocaptopril compounds and uses thereof

ABSTRACT

Compounds which are the reaction product of allicin and ACE-inhibiting compounds are useful in treating hypertension, elevated triglycerides, and elevated insulin.

FIELD OF THE INVENTION

[0001] The present invention relates to allylmercaptocaptopril andderivatives thereof which are useful in treating hypertension, elevatedtriglycerides and hyperglycemia.

BACKGROUND OF THE INVENTION

[0002] Captopril (D-3-mercapto-2-methylpropanoyl-L-proline) and relatedazetidine and proline derivatives are competitive inhibitors ofangiotensin-converting enzyme (ACE) that block the conversion ofangiotensin I to angiotensin II. Captopril and its derivatives are usedas antihypertensive agents in treating most forms of hypertension (U.S.Pat. No. 4,046,889, Ondetti et al, 1977; Thind, 1990; Cushman et al,1991. Migdalof et al. 1984; Materson et al, 1994)

[0003] Captopril contains a free sulfhydryl group and is quite stable inaqueous solution. However, in the blood or plasma of mammals, includinghumans, it is rapidly oxidized to its disulfide dimer and is involved inother disulfide exchange reactions. Captopril was found to bindcovalently but reversibly to plasma proteins, cysteine, and glutathione(Migdalof et al, 1984)

[0004] Unfortunately, rather high doses of captopril are required toreduce blood pressure. This phenomenon may be because most of thecaptopril is used up in reactions with serum protein, to reduce —S—Sbonds in proteins, and to form the mixed disulfide of protein-captopril.Thus, only a small amount of free captopril, or captopril recycled fromthe mixed disulfide with proteins, glutathione, and cysteine, remainsfor inhibiting ACE. Therefore, larger amounts of captopril are requiredas compared with other non-thiol containing ACE inhibitors. This mayexplain the discrepancy between the in vitro and in vivo activity ofcaptopril.

[0005] It has recently been shown that allicin (dithiosulfinate), aproduct of crushed garlic, which the present inventors preparedsemi-synthetically (international patent WO 97/39115), also possessesantihypertensive properties. Other studies reported the remedial effectsof allicin on cardiovascular risk factors, mainly on serum cholesterol,triglycerides levels, as well as lipoprotein balance, streak formation,and thrombogenesis in animals and in humans (Augusti et al, 1974; Eilatet al, 1995; Lawson, 1998; Abramovitz et al, 1999). Lipid loweringeffect is one of the earliest established properties of garlicpreparations, which also have a hypotensive effect as shown by Loeper etal (1921), which effect was confirmed by others in humans (Damrau, 1941;Petkov, 1979) and in animals (Chanderkar et al, 1973; Banerjee, 1979;Malik et al, 1981; Foushee et al, 1982; Ruffin et al, 1983; Auer et al,1990; Aqel et al, 1991).

[0006] Two possible mechanisms for the action of allicin have beensuggested. One involves the antioxidant activity of allicin, while theother mechanism is that the particular structure of allicin, asactivated disulfide, makes it a good candidate for interaction with theSH groups of proteins and low molecular weight thiols. Allicin, which isa very reactive compound, also disappears within a few minutes afterbeing mixed with blood, due to its fast penetration through cellmembranes, and its reaction with free thiol containing compounds, mainlyreduced glutathione (GSH). From studies conducted by the presentinventors, Rabinkov et al (1998) and Miron et al (2000), it appears thatthe active principal of allicin is the allylmercapto moiety (AM), whichblocks thiol containing enzymes or reacts as a very efficientantioxidant.

SUMMARY OF THE INVENTION

[0007] It is an object of the present invention to overcome theaforesaid deficiencies in the prior art.

[0008] It is another object of the present invention to producecompounds which have hypotensive effects.

[0009] It is a further object of the present invention to producecompounds which lower triglycerides and insulin.

[0010] The compounds of the present invention have the formula

[0011] wherein:

[0012] R¹ and R³ are each hydrogen, lower alkyl, or phenyl-lower alkyl;

[0013] R² is hydrogen, hydroxy, lower alkyl or carboxyl;

[0014] Q is —CH═CH₂ or —C≡CH;

[0015] m is 0-10; and

[0016] n is 0, 1, or 2.

[0017] Pharmaceutical compositions for treating hypertension include thecompounds of the present invention, as active principle, along with asuitable pharmaceutically acceptable excipient or carrier. The activeprinciple is present in an amount effective to reduce blood pressure.

[0018] The present invention further comprehends methods for treatinghypertension by administering to a patient in need of reduction ofhypertension an effective amount of a compound or composition of thepresent invention. Methods of treating elevated triglycerides and/orelevated insulin levels by administering such compounds or compositionsare also encompassed by the present invention.

[0019] The present invention also includes a method for preparing thecompounds of the present invention by reacting an HCE-inhibiting prolinederivative compound with allicin or a derivative thereof.

[0020] The nature and objects of the present invention will be betterunderstood upon consideration of the following detailed-description inconjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021]FIG. 1 illustrates inhibition of papain activity by CPSSA atvarious concentrations.

[0022]FIG. 2 shows inhibition of ACE by various concentrations of CPSSA.

[0023]FIG. 3 illustrates the effect of CPSSA and captopril on bloodpressure in rats.

[0024]FIG. 4 shows the effect of CPSSA and captopril on triglycerideslevel in rats' sera.

[0025]FIG. 5 shows the effect of CPSSA and captopril on insulin level inrats' sera.

DETAILED DESCRIPTION OF THE INVENTION

[0026] The compounds of the present invention inhibit the conversion ofthe decapeptide angiotensin I to angiotensin II, and therefore they areuseful in reducing or relieving angiotensin related hypertension, and inreducing triglycerides and insulin levels. The action of the enzymerenin on angiotensinogen, a pseudoglobulin in blood plasma, producesangiotensin I. Angiotensin I is converted by angiotensin convertingenzyme (ACE) to angiotensin II, which is an active pressor substancewhich has been implicated as the causative agent in various forms ofhypertension in many mammalian species. The compounds of the presentinvention intervene in the renin→angiotensin I→angiotensin II sequenceby inhibiting angiotensin converting enzyme and reducing or eliminatingthe formation of the pressor substance angiotensin II. Thus, byadministering a composition containing at least one of the compounds ofthe present invention, angiotensin dependant hypertension can bealleviated.

[0027] The compounds of the present invention combine the advantages ofACE-inhibiting azetidine and proline derivatives with the advantages ofallicin, both of which are effective agents against hypertonia, eachcompound operating by a different mechanism. The product of the reactionbetween captopril per se and allicin is allylmercaptocaptopril (CPSSA),a non-symmetric disulfide (Scheme 1) which combines both the specificpharmacological activity of captopril and the beneficial properties ofdiallyldithiosulfinate (allicin)

[0028] Additionally, diners and derivatives of allicin, such as ajoine,which also react with thiols, can be used to prepare ACE-inhibitingcompounds according to the present invention. For purposes of thepresent invention, “derivatives of allicin” refers to diners, trimers,etc. as well as allicin compounds in which one or more of the carbonatoms are substituted which react with thiols.

[0029] Compounds according to the present invention can also be preparedfrom the acetyleno (propargyl) analogue of allicin,

[0030] Dipropargyldithiosulfinate.

[0031] This propargyl analogue can be used to prepare the propargylderivative of captopril, propargylmercaptocaptopril, as it performs thesame thiolation reaction.

[0032] More generally, when Q is either allyl or propargyl, thefollowing reaction occurs:

[0033] where

[0034] R¹ is hydrogen, lower alkyl or phenyl-lower alkyl;

[0035] R² is hydrogen, hydroxy, lower alkyl, R₃CO, or carboxyl;

[0036] R³ is hydrogen, lower alkyl or phenyl-lower alkyl;

[0037] m is 0-10; and

[0038] n is 0, 1, or 2.

[0039] The stereoisomers in which m is 1 and proline is in the L-formare especially preferred.

[0040] The lower alkyl groups represented by any of the variablesinclude straight and branched chain C₁-C₆ hydrocarbon radicals, such asmethyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl,isopentyl, hexyl, and the like. The lower alkoxy groups are of the samekind having from 1 to 7 carbon atoms linked to oxygen, such as methoxy,ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, t-butoxy, and the like.The C₁-C₄ members of this group, particularly the C₁ and C₂ members, ofboth types are preferred. Phenylmethyl is the preferred phenyl-loweralkyl group.

[0041] The lower alkanoyl groups are those which have acyl radicals ofthe lower (C₂-C₇) fatty acids, such as acetic, propionyl, butyryl,isobuytyryl, and the like. Similarly, those lower alkanoyl groups havingup to four carbon atoms, and particularly acetyl, are preferred.

[0042] Captopril and its derivatives can be prepared by methodsdisclosed in U.S. Pat. No. 4,046,889, the entire contents of which beinghereby incorporated by reference.

[0043] CPSSA and its derivatives and related compounds react verysluggishly with serum proteins where the thiol groups are mostly in thedisulfide form. Thus, the compounds of the present invention are stablein blood or plasma of mammals and high doses of the compounds are notneeded to produce an anti-hypertensive effect.

[0044] Compositions within the scope of the present invention includeall compositions wherein the active ingredient is contained in an amounteffective to achieve its intended purpose. While individual needs vary,determination of optimal ranges of effective amounts of each compound iswithin the skill of the art. Typical dosages comprise 0.01 to 100 mg/kgbody weight. The preferred dosages comprising 0.1 to 100 mg/kg bodyweight. The most preferred dosages comprise 1 to 50 mg/kg body weight.

[0045] Pharmaceutical compositions for administering the activeingredients of the present invention preferably contain, in addition tothe pharmacologically active compound, suitable pharmaceuticallyacceptable carriers comprising excipients and auxiliaries whichfacilitate processing of the active compounds into preparations whichcan be used pharmaceutically. Preferably, the preparations, particularlythose preparations which are administered orally and which can be usedfor the preferred type of administration, such as tablets, dragees, andcapsules, and also preparations which can be administered rectally, suchas suppositories, as well as suitable solutions for administration byinjection or orally, contain from about 0.01 to about 99 percent byweight, preferably from about 20 to 75 percent by weight, activecompound(s), together with the excipient. For purposes of the presentinvention, all percentages are by weight unless otherwise indicated. Inaddition to the following described pharmaceutical composition, thecompounds of the present invention can be formulated as inclusioncomplexes, such as cyclodextrin inclusion complexes.

[0046] Examples of pharmaceutically acceptable acid addition salts foruse in pharmaceutical compositions according to the present inventioninclude those derived from mineral acids, such as hydrochloric,hydrobromic, phosphoric, metaphosphoric, nitric, and sulfuric acids, andorganic acids such as tartaric, acetic, citric, malic, lactic, fumaric,benzoic, glycolic, gluconic, succinic, and arylsulfonic, such asp-toluenesulfonic, acids.

[0047] The pharmaceutically acceptable carriers include vehicles,adjuvants, excipients, or diluents that are well known to those skilledin the art and which are readily available. It is preferred that thepharmaceutically acceptable carrier be one which is chemically inert tothe active compounds and which has no detrimental side effects ortoxicity under the conditions of use.

[0048] The choice of carrier is determined partly by the particularactive ingredient, as well as by the particular method used toadminister the composition. Accordingly, there is a wide variety ofsuitable formulations of the pharmaceutical compositions of the presentinvention. Formulations can be prepared for oral, aerosol, parenteral,subcutaneous, intravenous, intraarterial, intramuscular,intraperitoneal, intratracheal, rectal, and vaginal administration.

[0049] Suitable excipients are, in particular, fillers such assaccharides, for example, lactose or sucrose, mannitol or sorbitol,cellulose preparations and/or calcium phosphates, for example,tricalcium phosphate or calcium hydrogen phosphate, as well as binderssuch as starch paste using, for example, maize starch, wheat starch,rice starch, potato starch, gelatin, tragacanth, methyl cellulose,hydroxypropylmethylcellulose, sodium carboxymethylcelullose, and/orpolyvinyl pyrrolidine.

[0050] Suitable formulations for parenteral administration includeaqueous solutions of the active compounds in water-soluble form, such aswater-soluble salts. In addition, suspensions of the active compounds asappropriate oily injection suspensions may be administered. Suitablelipophilic solvents or vehicles include fatty oils, for example, sesameoil, or synthetic fatty acid esters, for example, ethyl oleate ortriglycerides. Aqueous injection suspensions may contain substanceswhich increase the viscosity of the suspension, including, for example,sodium carboxymethyl cellulose, sorbitol, and/or dextran. Optionally,the suspension may also contain stabilizers.

[0051] Other pharmaceutically acceptable carries for the activeingredients according to the present invention are liposomes,pharmaceutical compositions in which the active ingredient is containedeither dispersed or variously present in corpuscles contained eitherdispersed or variously present in corpuscles consisting of aqueousconcentric layers adherent to lipid layers. The active ingredient may bepresent both in the aqueous layer and in the lipidic layer, inside oroutside, or, in any event, in the non-homogeneous system generally knownas a liposomic suspension.

[0052] The hydrophobic layer, br lipid layer, generally, but notexclusively, comprises phospholipids such as lecithin and sphingomyelin,steroids such as cholesterol, more or less ionic surface activesubstances such as dicetyl phosphate, stearylamine, or phosphatidicacid, and/or other materials of a hydrophobic nature.

[0053] The compounds may also be formulated for transdermaladministration, for example in the form of transdermal patches so as toachieve systemic administration. Formulations suitable for oraladministration can consists of liquid solutions such as effectiveamounts of the compound(s) dissolved in diluents such as water, saline,or orange juice; capsules, tables, sachets, lozenges, and troches, eachcontaining a predetermined amount of the active ingredient as solids orgranules; powders, suspensions in an appropriate liquid; and suitableemulsions. Liquid formulations may include diluents such as water andalcohols, e.g., ethanol, benzyl alcohol, and the polyethylene alcohols,either with or without the addition of a pharmaceutically acceptablesurfactant, suspending agents, or emulsifying agents. Capsule forms canbe of the ordinary hard- or soft-shelled gelatin type containing, forexample, surfactants, lubricant, and inert fillers, such as lactose,sucrose, calcium phosphate, and corn starch. Tablet forms can includeone or more of lactose, sucrose, mannitol, corn starch, potato starch,alginic acid, microcrystalline cellulose, acacia, gelatin, guar gum,colloidal silicon dioxide, croscaramellose sodium, talc, magnesiumstearate, calcium stearate, zinc stearate, stearic acid, and otherpreservatives, flavoring agents, and pharmaceutically acceptabledisintegrating agents, moistening agents preservatives flavoring agents,and pharmacologically compatible carriers. Lozenge forms can comprisethe active ingredient in a carrier, usually sucrose and acacia ortragacanth, as well as pastilles comprising the active ingredient in aninert base such as gelatin or glycerin, or sucrose and acacia. Emulsionsand the like can contain., in addition to the active ingredient, suchcarriers as are known in the art.

[0054] Formulations suitable for parenteral administration includeaqueous and non-aqueous, isotonic sterile injection solutions, which cancontain anti-oxidants, buffers, bacteriostats, and solutes that renderthe formulation isotonic with the blood of the intended recipient, andaqueous and non-aqueous sterile suspensions that can include suspendingagents, solubilizers, thickening agents, stabilizers, and preservatives.The compounds can be administered in a physiologically acceptablediluent in a pharmaceutical carriers, such as a sterile liquid ormixture of liquids, including water, saline, aqueous dextrose andrelated sugar solutions, an alcohol such as ethanol, isopropanol, orhexadecyl alcohol, glycols such as propylene glycol or polyethyleneglycol, glycerol ketals such as 2,2-dimethyl-1,3-dioxolane-4-methanol,ethers such as poly(ethylene glycol) 400, oils, fatty acids, fatty acidesters or glycerides, or acetylated fatty acid glycerides, without theaddition of a pharmaceutically acceptable surfactants, such as soap or adetergent, suspending agent, such as carbomers, methylcellulose,hydroxypropylmethylcellulose, or carboxymethylcellulose, or emulsifyingagents and other pharmaceutical adjuvants.

[0055] Oils which can be used in parenteral formulations includepetroleum, animal, vegetable, or synthetic oils. Specific examples ofoils include peanut, soybean, sesame, cottonseed, corn, olive,petrolatum, and mineral. Fatty acids can be used in parenteralformulations, including oleic acid, stearic acid, and isostearic acid.Ethyl oleate and isopropyl myristate are examples of suitable fatty acidesters. Suitable salts for use in parenteral formulations include fattyalkali metal, ammonium, and triethanolamine salts, and suitabledetergents include cationic detergents such as dimethyl dialkyl ammoniumhalides, and alkyl pyridimium halides; anionic detergents such asdimethyl olefin sulfonates, alkyl, olefin, ether, and monoglyceridesulfates and sulfosuccinates; polyoxyethylenepolypropylene copolymers;amphoteric detergents such as alkyl-beta-aminopropionates and2-alkyl-imidazoline quaternarry ammonium salts; and mixtures thereof.

[0056] Parenteral formulations typically contain from about 0.5 to 25%by weight of the active ingredient in solution. Suitable preservativesand buffers can be used in these formulations. In order to minimize ofeliminate irritation at the site of injection, these compositions maycontain one or more nonionic surfactants having a hydrophilic-lipophilicbalance (HLB) of from about 12 to about 17. The quantity of surfactantin such formulations ranges from about 5 to about 15% by weight.Suitable surfactants include polyethylene sorbitan fatty acid esters,such as sorbitan monooleate and the high molecular weight adducts ofethylene oxide with a hydrophobic base, formed by the condensation ofpropylene oxide with propylene glycol. The parenteral formulations canbe present in unit dose or multiple dose sealed containers, such asampules and vials, and can be stored in a freeze-dried (lyophilized)condition requiring only the addition of the sterile liquid carrier,e.g., water, for injections immediately prior to use. Extemporaneousinjection solutions and suspensions can be prepared from sterilepowders, granules, and tablets of the kind previously described.

[0057] Additionally, the active ingredients can be formulated intosuppositories by mixing the active ingredient with a variety of bases,including emulsifying bases or water-soluble bases. Formulationssuitable for vaginal administration may be in the form of pessaries,tampons, creams, gels, pastes, foam, or spray formulations containing,in addition to the active ingredient, such carriers as are known in theart to be appropriate.

[0058] The active ingredients can be used as functionalized congenersfor coupling to other molecules, such as amines and peptides. The use ofsuch congeners provides for increased potency, prolonged duration ofaction, and prodrugs. Water solubility is also enhanced, which allowsfor reduction, if not complete elimination, of undesirable binding toplasma proteins and partition in to lipids. Accordingly, improvedpharmacokinetics can be realized.

[0059] Any number of assays well known in the art, such as that ofCarmel et al (1979), may be used to test whether a particular compoundsuspected of being an ACE inhibitor is effective as such.

[0060] In determining the dosages of the compounds to be administered,the dosage and frequency of administration is selected in relation tothe pharmacological properties of the specific active ingredients.Normally., at least three dosage levels should be used. In toxicitystudies in general, the highest dose should reach a toxic level but besublethal for most animals in the group. If possible, the lowest doseshould induce a biologically demonstrable effect. These studies shouldbe performed in parallel for each compound selected.

[0061] Additionally, the ID₅₀ level of the active ingredient in questioncan be one of the dosage levels selected, and the other two selected toreach a toxic level. The lowest dose that dose not exhibit abiologically demonstrable effect. The toxicology tests should berepeated using appropriate new doses calculated on the basis of theresults obtained. Young, healthy mice or rats belonging to awell-defined strain are the first choice of species, an the firststudies generally use the preferred route of administration. Controlgroups given a placebo or which are untreated are included in the tests.Tests for general toxicity, as outlined above, should normally berepeated in another non-rodent species, e.g., a rabbit or dog. Studiesmay also be repeated using alternate routes of administration.

[0062] Singe dose toxicity tests should be conducted in such a way thatsigns of acute toxicity are revealed and the mode of death determined.The dosage to be administered is calculated on the basis of the resultsobtained in the above-mentioned toxicity tests. It may be desired not tocontinue studying all of the initially selected compounds. Data onsingle dose toxicity, e.g., ID₅₀, the dosage at which half of theexperimental animals die, is to be expressed in units of weight orvolume per kg of body weight and should generally be furnished for atleast two species with different modes of administration. In addition tothe ID₅₀ value in rodents, it is desirable to determine the highesttolerated dose and/or lowest lethal dose for other species, i.e., dogand rabbit.

[0063] When a suitable and presumably safe dosage level has beenestablished as outlined above, studies on the drug's chronic toxicity,its effect on reproduction, and potential mutagenicity may also berequired in order to ensure that the calculated appropriate dosage rangewill be safe, also with regard to these hazards.

[0064] Pharmacological animal studies on pharmacokinetics revealing,e.g., absorption, distribution, biotransformation, and excretion of theactive ingredient and metabolites are then performed. Using the resultsobtained, studies on human pharmacology are then designed. Studies ofthe pharmacodynamics and pharmacokinetics of the compounds in humansshould be performed in healthy subjects using the routes ofadministration intended for clinical use, and can be repeated inpatients. The dose-response relationship when different doses are given,or when several types of conjugates or combinations of conjugates andfree compounds are given, should be studied in order to elucidate thedose-response relationship (dose vs. plasma concentration vs. effect),the therapeutic range, and the optimum dose interval. Also, studies ontime-effect relationship, e.g., studies into the time-course of theeffect and studies on different organs in order to elucidate the desiredand undesired pharmacological effects of the drug, in particular onother vital organ systems, should be performed.

[0065] The compounds of the present invention are then ready forclinical trials to compare the efficacy of the compounds to existingtherapy. A dose-response relationship to therapeutic effect and for sideeffects can be more finely established at this point.

[0066] The amount of compounds of the present invention to beadministered to any given patient must be determined empirically, andwill differ depending upon the condition of the patients. Relativelysmall amounts of the active ingredient can be administered at first,with steadily increasing dosages if no adverse effects are noted. Ofcourse, the maximum safe toxicity dosage as determined in routine animaltoxicity tests should never be exceeded.

[0067] The compounds of the present invention can be administered in asingle dose, or preferably two or four daily doses, provided on thebasis of about 0.01 to 50 mg per kilogram per day, preferably about 0.1to about 25 mg per kilogram per day, to reduce blood pressure. Thecompounds are preferably administered orally, but parenteral routes,such as subcutaneously, intramuscularly, intravenously, orintraperitoneally, can also be used.

[0068] The compounds of the present invention formulated in compositionssuch as tablets, capsules, or elixirs for oral administration, or insterile solutions or suspensions for parenteral administration. About 1to about 250 mg of a compound or mixture of compounds is compounded witha pharmaceutically acceptable vehicle, carrier, excipient, binder,preservative, stabilizer, flavor, etc., in a unit dosage form. Theamount of active substance in these compositions or preparations is suchthat a suitable dosage in the range indicated is obtained.

[0069] Materials and Methods

[0070] Pure allicin was produced by interaction of the syntheticsubstrate allicin with stabilized alliinase as described previously inMirelman et al, international patent WO 97/39115. Fructose was purchasedfrom Harlan, Teklad (Madison, Wis.). Captopril was purchased form Sigma,St. Louis, Mo. Sprague-Dawley rats were purchased form ANILAB,Tal-Shahar, Israel.

[0071] Captopril, allylmercaptocaptopril, and allicin were separated byHPLC using an LKB HPLC system with an SP 4290 integrator(Spectraphysics). Separation was effected on a LiChrosornb RP-18 (7 mm)column using 60% methanol in water containing 0.1% formic acid or 0.05%trifluoroacetic acid as an eluant. The flow rate was 0.55 ml/minute.

[0072] CPSSA (0-5 mM) modification of activated and gel-filtered papainwas conducted at room temperature in 50 mM sodium acetate, 2 mM EDTA pH6.1. The inhibited papain was reactivated with 5 mM reduced glutathione.

[0073] The activity of angiotensin-converting enzyme was assayedaccording to Carmel et al (1979).

[0074] Animal experiments were conducted on Sprague-Dawley ratsaccording to Reaven's model (Reaven et al, 1991), in which rats feedingon a fructose-enriched diet developed high blood pressure as well ashigh insulin and high triglyceride levels. This model was previouslyused to test the effect of different angiotensin-converting enzymeinhibitors on metabolic parameters and blood pressure Erlich et al(1995), Erlich et al (1996). In the present study, the effects of CPSSAand captopril on blood pressure, as well as serum levels oftriglycerides and insulin, were compared.

[0075] RESULTS

EXAMPLE 1 Synthesis and Isolation of S-allylmercaptocaptopril (CPSSA)

[0076] The reaction of allicin and captopril was performed as follows:

[0077] Captopril (217 mg, 1 mmole) in 7.5 ml water pre-adjusted to pH5.5, was added dropwise to allicin (90 mg, 0.55 mmole) dissolved in 3 mlabsolute ethanol. The reaction mixture was magnetically stirred for15-20 minutes at room temperature. Excess allicin was extracted byether, and the water phase was acidified with HCL and extracted withethyl acetate. The organic phase was dried by rotor evaporation,re-dissolved either in ethanol and dried by Speed Vac centrifugation orre-dissolved in water and dried by lyophilization. The yield of thereaction was 90%. The reaction product was detected by HPLC analysis (RT14.1 minutes). The structure was confirmed by NMR and MS.

EXAMPLE 2 SH Modification of Papain

[0078] Incubation of papain with allylmercaptocaptopril caused asignificant decrease of enzyme activity. The degree of inhibition wasconcentration dependent. The activity of the inactivated papain could berestored by reduced glutathione.

[0079] Activated papain was mixed with various concentrations of CPSSAfor 10 minutes at room temperature in 50 mM sodium acetate, 2 mM EDTAbuffer, pH 6.5. The residual enzyme activity was measured by monitoringthe rate of hydrolysis of the substrate benzoyl arginine-p-nitro anilideat 382 nm. The results are shown in FIG. 1.

EXAMPLE 3 Effect of CPSSA on Angiotensin Converting Enzyme Activity InVitro

[0080] In order to determine if CPSSA reacts in a similar way tocaptopril, which inhibits the activity of angiotensin converting enzyme,serial dilutions of CPSSA were prepared. Samples were added to areference serum and the activity of the enzyme was monitored as shown inFIG. 2. The inhibition was concentration dependant and essentially doesnot differ from the inhibition profile obtained with captopril.

EXAMPLE 4 Effect of CPSSA on Blood Pressure, Serum Triglycerides,Insulin Concentrations, and Body Weight

[0081] Model Sprague-Dawley male rates, five rats/group, 220-240 g bodyweight, were fed with a fructose-rich diet for three weeks, followed bytwo weeks of treatment with either CPSSA or captopril predissolved inthe drinking water in doses of CPSSA of 40 and 57 mg/kg and 80 mg/kgcaptopril, together with the fructose-rich diet. The control group wasfed only the fructose-rich diet. Measurements of body weight, bloodpressure, serum levels of triglycerides and insulin were conducted at 0,3, and 5 weeks into the treatment. As can readily be seen from FIGS.3-5, CPSSA significantly decreased blood pressure (FIG. 3) and reducedthe serum levels of triglycerides (FIG. 4) and insulin (FIG. 5) to nearnormal levels once administration of CPSSA occurred. Similar resultswere obtained with captopril with doses that were nearly double that ofCPSSA. CPSSA, like captopril, decreased serum insulin levels to normalvalues in model animals (FIG. 5), but CPSSA appears to be more activethan captopril in decreasing levels of triglycerides (FIG. 4). Noeffects on body weight were found in either treatment.

[0082] Pharmaceutical compositions according to the present inventioncan be administered by any convenient route, including parenteral,subcutaneous, intravenous, intramuscular, intraperitoneal, ortransdermal. Alternatively or concomitantly, administration may be bythe oral route. The dosage administered depends upon the age, health,and weight of the recipient, nature of concurrent treatment, if any, andthe nature of the effect desired.

[0083] The foregoing description of the specific embodiments will sofully reveal the general nature of the invention that others can, byapplying current knowledge, readily modify and/or adapt for variousapplications such specific embodiments without undue experimentation andwithout departing from the generic concept. Therefore, such adaptationsand modifications should and are intended to be comprehended within themeaning and range of equivalents of the disclosed embodiments. It is tobe understood that the phraseology or terminology employed herein is forthe purpose of description and not of limitation. The means andmaterials for carrying our various disclosed functions may take avariety of alternative forms without departing from the invention. Thus,the expressions “means to . . . ” and “means for . . . ” as may be foundin the specification above and/or in the claims below, followed by afunctional statement, are intended to define and cover whateverstructural, physical, chemical, or electrical element or structureswhich may now or in the future exist for carrying out the recitedfunction, whether or not precisely equivalent to the embodiment orembodiments disclosed in the specification above; and it is intendedthat such expressions be given their broadest interpretation.

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What is claimed is:
 1. Compounds of the formula:

where R¹ is hydrogen, lower alkyl or phenyl-lower alkyl; R² is hydrogen,hydroxy, lower alkyl, R₃CO, or carboxyl; R³ is hydrogen, lower alkyl orphenyl-lower alkyl; m is 0-10; n is 0, 1, or 2; and Q is —CH═CH₂ or—C≡CH.
 2. The compound according to claim 1, wherein m is 1 to
 5. 3. Thecompound according to claim 1, wherein R¹ is hydrogen or lower alkyl; R²and R³ are each hydrogen.
 4. The compound according to claim 1, whereinR² and R³ are each hydrogen.
 5. The compound according to claim 1,wherein R² is hydrogen.
 6. The L-form of the compound of claim
 1. 7. Thecompound according to claim 1, wherein n is
 1. 8. The compound accordingto claim 1, wherein R¹ is hydrogen or lower acetyl.
 9. The compoundaccording to claim 1, wherein R¹ is hydrogen or methyl.
 10. The compoundaccording to claim 1, wherein n is
 0. 11. The compound according toclaim 7, wherein R¹, R², and R³ are each hydrogen.
 12. The compoundaccording to claim 7, wherein R¹ is methyl and R² and R³ are eachhydrogen.
 13. The compound according to claim 11, wherein m is 1 and theproline is in the L-form.
 14. The compound according to claim 12,wherein m is 1 and the proline is in the L-form.
 15. The compoundaccording to claim 13, wherein m is 1 and the proline is in the L-form.16. The compound according to claim 1, wherein Q is —C═CH₂.
 17. Thecompound according to claim 1, wherein Q is —C≡CH.
 18. A method fortreating hypertension comprising administering to a patient in needthereof an effective amount of a compound according to claim
 1. 19. Apharmaceutical composition for treating hypertension comprising aneffective amount to reduce blood pressure of at least one compoundaccording to claim 1 and a pharmaceutically acceptable carrier.
 20. Amethod for preparing compounds for treating hypertension comprisingreacting an ACE-inhibiting proline derivative compound with allicin or aderivative thereof.
 21. The method according to claim 20, wherein theACE-inhibiting proline derivative is captopril.
 22. A method fortreating elevated triglycerides comprising administering to a patient inneed thereof an effective amount of a compound according to claim
 1. 23.A method for treating elevated insulin levels comprising administeringto a patient in need thereof an effective amount of a compound accordingto claim 1.